The present invention relates to a gun for cutting out sheet metal, of the type comprising a body having an axis and supporting coaxially, at one end, a cutting head comprising an electrode-carrying assembly extending into a nozzle comprising a plasmagenic gas outlet, for cutting out circles of sheet metal, particularly for the formation of small cutouts about spot welds between two pieces of sheet metal, so as to separate them. This operation, which is commonly called "unbuttoning" of spot welded metal sheets is at present effected mechanically:
by hammer and chisel;
by grinding;
by a special cutting tool mounted on a drill.
None of these means permits performing properly and rapidly this type of operation, particularly for automobile repair or if access to the welds is limited.
In the first case, manual cutting out is difficult and imprecise and gives rise to deformations in the piece that one would like to reuse. Grinding, although neater, is a long and delicate operation, because the tool used is bulky. Cutting out requires a costly tool, whose use is delicate and which moreover gives rise to deformations of the support sheet metal.